Just in case anyone is considering a used IBM server – I didn’t see much of a difference on my last energy bill thankfully, so that’s a relief. Compared to the summer months running a window unit AC there wasn’t much of a change in my electric since I started using it. (It’s only on when I’m rendering stuff, but I’ve been keeping long renders going pretty steady for the last few weeks at least, so it’s been more on than off so far…)
Usage June - today.

Staying a little more on topic for the thread – FWIW I’m using a very untweaked arch linux install on my laptops and this server, all just using ALSA & JACK without any special tuning.
Hop on in, the linux is fine!
(YMMV but I think it generally helps to go with a rolling release distro that is based on a recent kernel – so, debian, ubuntu and friends might not be the best choice depending on the hardware you want to use…)